Telematics units within mobile vehicles provide subscribers with connectivity to a telematics service provider (TSP). The TSP provides subscribers with an array of services ranging from emergency call handling and stolen vehicle recovery to diagnostics monitoring and turn-by-turn navigation. Telematics units are often provisioned and activated at a point of sale when a subscriber purchases a telematics-equipped vehicle. Upon activation, the telematics unit can be utilized to provide a subscriber with the telematics services.
One of the services conventionally provided by TSPs is Global Positioning System (GPS) navigation, which may include the provision of Turn-by-Turn (TBT) directions. To use GPS navigation, a user of the telematics unit may enter a destination, and the GPS component of the telematics unit may provide directions (e.g. through a display and/or through vocal instructions) to the user based on a calculated course from the user's current location to the user's destination. When a user does not follow the directions and goes off-course (i.e., when the position of the vehicle is not on the calculated course), the GPS unit may recalculate a new course for the user to take based on the vehicle's position when it goes off-course. The position of the telematics unit is determined through reception of GPS signals or a combination of GPS signals and dead reckoning (DR).
In many circumstances, such as in urban canyon environments, the GPS signal received by a telematics unit may not accurately indicate the vehicle's actual position. Thus, the user may be provided with incorrect information as to the user's present location. Furthermore, the user may be notified that the vehicle has gone off-course when it is in actuality following the directions originally provided to the telematics unit.
The inventors have created the above body of information merely for the convenience of the reader; the foregoing is a discussion of problems discovered and/or appreciated by the inventors, and is not an attempt to review or catalog the prior art.